Clinicaltrials Search Studies
clinicaltrials_search_studiesRead-onlyIdempotent
Search clinical trials by condition, intervention, location, status, and phase. Retrieve study details with customizable fields and pagination.
Instructions
Search for clinical trial studies from ClinicalTrials.gov. Supports full-text and field-specific queries, status/phase/geographic filters, pagination, sorting, and field selection. Returns a compact per-study index by default; pass the fields parameter to get specific leaves at full fidelity — full study records are ~70KB each.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| sort | No | Sort order. Format: FieldName:asc or FieldName:desc. E.g., "LastUpdatePostDate:desc", "EnrollmentCount:desc". Max 2 fields comma-separated. For "largest trials" queries, pair EnrollmentCount:desc with advancedFilter "AREA[StudyType]INTERVENTIONAL" — the top enrollment counts are observational registry/claims studies enrolling tens of millions. Enrollment counts are sponsor-reported and not validated upstream beyond the unknown-enrollment sentinel exclusion. Use clinicaltrials_get_field_definitions to find sortable field names. | |
| query | No | General free-text search across all fields. Plain words plus AND, OR, NOT. `[ ]` are reserved (advancedFilter AREA[] only); `( )` group sub-expressions and work when matched; `,` acts as AND. For field-scoped searches, use the dedicated *Query parameters (conditionQuery, interventionQuery, etc.) or advancedFilter with AREA[FieldName]value. | |
| fields | No | PascalCase leaf names to return; strongly recommended since full records are ~70KB. Common leaves: NCTId, BriefTitle, BriefSummary, OverallStatus, Phase, LeadSponsorName, Condition. Call clinicaltrials_get_field_definitions with a concept query (e.g., "adverse events", "eligibility") to find the exact leaf for any concept. | |
| nctIds | No | Filter to specific NCT IDs for batch lookups. | |
| pageSize | No | Results per page, 1–200. | |
| geoFilter | No | Geographic proximity filter. Format: distance(lat,lon,radius). E.g., "distance(47.6062,-122.3321,50mi)" for studies within 50 miles of Seattle. When set, each study's locations are re-sorted by proximity to the center so the nearest matched site leads, annotated with its distance in miles; the full location list is preserved. | |
| pageToken | No | Pagination cursor from a previous response. | |
| countTotal | No | Include total study count in response. Only computed on the first page. | |
| titleQuery | No | Search within study titles and acronyms only. Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| phaseFilter | No | Filter by trial phase. Values: EARLY_PHASE1, PHASE1, PHASE2, PHASE3, PHASE4, NA. | |
| outcomeQuery | No | Search within outcome measure fields. Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| sponsorQuery | No | Sponsor/collaborator name search. Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| statusFilter | No | Filter by study status. Values: RECRUITING, COMPLETED, ACTIVE_NOT_RECRUITING, NOT_YET_RECRUITING, ENROLLING_BY_INVITATION, SUSPENDED, TERMINATED, WITHDRAWN, UNKNOWN, WITHHELD, NO_LONGER_AVAILABLE, AVAILABLE, APPROVED_FOR_MARKETING, TEMPORARILY_NOT_AVAILABLE. | |
| locationQuery | No | Location search — city, state, country, or facility name. Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| advancedFilter | No | Advanced filter using AREA[FieldName]value syntax. Examples: "AREA[StudyType]INTERVENTIONAL", "AREA[EnrollmentCount]RANGE[100, 1000]", "AREA[Phase]PHASE2 AND AREA[StudyType]INTERVENTIONAL", "(AREA[Phase]PHASE3 OR AREA[Phase]PHASE4) AND AREA[StudyType]INTERVENTIONAL". AND/OR/NOT join complete AREA[FieldName]value expressions; parentheses group them. Call clinicaltrials_get_field_definitions to find AREA[]-compatible field names. | |
| conditionQuery | No | Condition/disease-specific search. E.g., "Type 2 Diabetes", "non-small cell lung cancer". Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| interventionQuery | No | Intervention/treatment search. E.g., "pembrolizumab", "cognitive behavioral therapy". Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| includeUnknownEnrollment | No | Include studies whose EnrollmentCount is the upstream "unknown" sentinel (99999999). Excluded by default — the sentinel pollutes RANGE[N, MAX] queries and EnrollmentCount:desc sorts. Set true for data-quality audits or when targeting unknown-enrollment studies specifically. |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| notice | No | Recovery guidance when no studies matched — echoes the constraint and suggests how to broaden. Absent on pages with results. | |
| studies | Yes | Matching studies. By default each entry is a COMPACT index projection — nctId, briefTitle, overallStatus, phases, enrollmentCount, leadSponsor, conditions, and a bounded locations summary ({ total, nearest }) — mirroring the rendered result, NOT the full ~70KB record. Pass the fields parameter to receive exactly the requested leaves at full fidelity instead (e.g. all locations). Fetch a full single record with clinicaltrials_get_study_record. | |
| totalCount | No | Total matching studies (first page only when countTotal=true). | |
| nextPageToken | No | Token for the next page. Absent on last page. | |
| searchCriteria | No | Echo of active query/filter criteria applied to this search, including sentinelFilterActive when the default unknown-enrollment exclusion is in effect. Present on every response. | |
| requestedFields | No | Echo of the explicit fields parameter — present only when the caller passed fields. Signals that studies carry the requested leaves at full fidelity (not the default compact index) and that the rendered truncation cap is lifted so all of them appear. |